Catalogues:
DEEP SKY
Messier Catalogue - Compiled by Charles Messier 1758-1782.
RCW Catalogue - Published by Alex Rodgers, Colin Campbell, and John Whiteoak in 1960.
DOUBLE STARS
Double Stars By Constellation and Separation - Online database query.
Washington Double Star Catalog - The WDS Catalog contains positions (J2000), discoverer designations, epochs, position angles, separations, magnitudes, spectral types, proper motions, and, when available, Durchmusterung numbers and notes for the components of 114,865 systems based on 813,262 means as of 26 May 2011.
GLOBULAR CLUSTERS
Catalog of Parameters For Milky Way Globular Clusters - This catalog contains basic parameters on distances, velocities, metallicities, luminosities, colors, and dynamical parameters for 157 objects classified as globular clusters in the Milky Way galaxy (Dec. 2010)
NEBULAE
Gum Catalogue - Compiled by Colin Gum of Stromlo Obesrvatory and published 1955.
Sharpless Catalogue - Stewart Sharpless published the second and final version of his famous nebula catalog in 1959.
OPEN CLUSTERS
WEBDA - Stellar clusters in the Galaxy & Magellanic Clouds.
WEBDA - Diameters of Open Star Clusters (van den Bergh).
SOLAR SYSTEM
The Astronomical Almanac - Contains precise ephemerides of the Sun, Moon, planets, and satellites, data for eclipses and other astronomical phenomena for a given year.
Software:
Cartes du Ciel - A free program, it enables you to draw sky charts, making use of the data in 16 catalogs of stars and nebulae. In addition the position of planets, asteroids and comets are shown.
Celestia - The free space simulation that lets you explore our universe in three dimensions. Celestia comes with a large catalog of stars, galaxies, planets, moons, asteroids, comets, and spacecraft. If that's not enough, you can download dozens of easy to install add-ons with more objects.
Orbitron - Orbitron is a satellite tracking system for radio amateur and observing purposes. It's also used by weather professionals, satellite communication users & astronomers.
Stellarium - Stellarium is a free open source planetarium for your computer. It shows a realistic sky in 3D, just like what you see with the naked eye, binoculars or a telescope.